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Prof. H. E. Armstrong and others. [Nov. 23, 



that accompanies the cyanide. Arrangements have been made which it is 

 hoped will permit of this problem being solved. 



We have been fortunate in having our attention attracted to a plant the 

 study of which promises to be of interest not only from the point of view 

 above set forth but also for other reasons which will be apparent when our 

 account is considered. In the course of our search for enzymes of the 

 emulsin type* we have examined a large number of Leguminosse and were 

 led, early in the summer of last year, to discover in Lotus corniculatus 

 (Bird's-foot trefoil) a plant in which such an enzyme is associated with a 

 cyanophoric glucoside. We may mention that another reason which led us 

 to select this plant and test it for hydrogen cyanide was the fact that 

 Dunstan and Henry had discovered this substance in Lotus arabicus — a plant 

 growing on the banks of the Nile — and that hydrogen cyanide had also been 

 found in Lotus australis. 



The first specimen tested was picked on the Thames, near Wargrave, 

 in June, 1910. It was found to contain hydrogen cyanide when tested by 

 Guignard's alkaline picrate paper : a slip of the yellow paper, enclosed in 

 a small tube with two or three grammes of the plant and a drop or two of 

 chloroform, soon darkened in colour and ultimately became brick-red. This 

 specimen of Lotus corniculatus was also found to contain an enzyme or 

 enzymes which acted readily both on linamarin and on prunasinf though but 

 slightly on amygdalin. 



Of several specimens obtained from the Heading district soon after the 

 first was picked, only one or two contained hydrogen cyanide ; moreover, the 

 cyanide could not be detected in a number of specimens picked in July in the 

 Harpenden district and also near Flitwick (Beds.). 



During the early part of August search was made for the plant all over 

 the Swanage district, in Dorsetshire. It was found growing on London 

 clay, on chalk, on Purbeck and Portland limestone and on Kimmeridge 

 clay but only in one or two cases was hydrogen cyanide detected ; no 

 difference was apparent between the plants from the various soils. 



In the latter part of August we met with the plant in Switzerland, in the Saas 

 Valley ; again no evidence of the presence of hydrogen cyanide was obtainable. 



In September and October we obtained a second set of specimens from the 

 Harpenden and Flitwick districts ; these also were tested without cyanide 

 being discovered. 



* Compare ' Koy. Soc. Proc.,' 1910, B, vol. 82, p. 349. 



t We propose to use this name for the glucoside prepared from amygdalin — amygdo- 

 or mandelo-nitrile-glucoside — sometimes spoken of by us in earlier communications as 

 Fischer's glucoside. 



